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<h1><a href="https://archiveofourown.org/works/22673335">Grizzly Rex, 2087</a> by <a class='authorlink' href='https://archiveofourown.org/users/John_Steiner/pseuds/John_Steiner'>John_Steiner</a></h1>

<table class="full">

<tr><td><b>Category:</b></td><td>Jurassic Park - All Media Types</td></tr>

<tr><td><b>Language:</b></td><td>English</td></tr>

<tr><td><b>Status:</b></td><td>Completed</td></tr>

<tr><td><b>Published:</b></td><td>2020-02-12</td></tr>

<tr><td><b>Updated:</b></td><td>2020-02-12</td></tr>

<tr><td><b>Packaged:</b></td><td>2021-05-18 02:26:48</td></tr>

<tr><td><b>Rating:</b></td><td>Not Rated</td></tr>

<tr><td><b>Warnings:</b></td><td>Creator Chose Not To Use Archive Warnings</td></tr>

<tr><td><b>Chapters:</b></td><td>1</td></tr>

<tr><td><b>Words:</b></td><td>1,778</td></tr>

<tr><td><b>Publisher:</b></td><td>archiveofourown.org</td></tr>

<tr><td><b>Story URL:</b></td><td>https://archiveofourown.org/works/22673335</td></tr>

<tr><td><b>Author URL:</b></td><td>https://archiveofourown.org/users/John_Steiner/pseuds/John_Steiner</td></tr>

<tr><td><b>Summary:</b></td><td><div class="userstuff">
              <p>A genetic engineer documents the experiment designed to create a gold standard of extinct species recovery by reversing evolution in chickens with the end goal of bringing a tyrannosaur to life. The account covers twelve generations, and ends with unexpected results that reshapes the scientific view of the Tyrant Lizard.</p>
            </div></td></tr>

<tr><td><b>Comments:</b></td><td>1</td></tr>

<tr><td><b>Kudos:</b></td><td>1</td></tr>

</table>

<a name="section0001"><h2>Grizzly Rex, 2087</h2></a>
<div class="story"><div class="userstuff module">
    
    <p>The most common question I got was, 'what possessed me? Hadn't I seen that nearly century old movie?'</p><p>Yes, and even in its day, real geneticists and real paleontologists said no and not even close. Besides, I wasn't prying original dino DNA source code out of fossilized amber anyway. In the last few decades fossil discoveries included more traces of residual proteins, not many mind you, but enough that with 2060's computing power I and my team were able to project what other genes were needed for a Tyrannosaur to evolve the features we now know it had.</p><p>With that, and in conjunction with the Restoration of Extinct Species Project, our team was tasked with creating the gold standard of returning long dead species to life. The thinking went that if we could breed a T-Rex out of modern descendants then any animal or plant driven to extinction by humanity should be possible.</p><p>The low hanging fruit was reinserting functioning genes into chickens for finger development, post-cloacal vertebrae, growth of teeth, and the original placement of a shoulder muscle, which in modern birds made the flight stroke possible. Our starting sample size was four thousand eggs, and from them we got nearly two hundred sixty chicks to survive hatching. The literature for this stage of the project was well-established back in 2034, although, with one gene per breed of chicken.</p><p>Stage two required a hearing before the ethics review board, whereon I presented the keynote statement and accepted the opening questions regarding the bioethics of reverse-engineering a bird capable of basal emotions, and assurances that the new breed could not, in its current incarnation, cause further harm to today's ecosystems that were already in post-collapse.</p><p>Once given the go-ahead we started allowing hens and rooster to breed. Yet, we didn't select the most retrograde chicks from the F1 generation. Instead, I and two other PhD's led grad students in halting fertilized embryos prior to their forth mytotic division, the point at which differentiation begins. We artificially rewrote certain genes according to what birds lost most recently in their evolution after the Cretaceous Period.</p><p>By the F2 generation we had something resembling the miniature version of Terror Birds that went extinct one point eight million years ago. Only our breed had teeth, however the keratin still grew on the maxilla and mandible leading a slightly broader beak than normal chickens.</p><p>It also led to a shift in their diet, requiring us to provide a steady supply of lab mice to our theropods in the making. While our strain of birds had fingers, they were undersized and rudimentary claws only grew on two of the fingers. It wasn't until the F3 and F4 generations in the following year that we got respectable appendages, which those birds were able to use in seizing mice rather than relying on their beaks alone.</p><p>In F5 we started to see what we were aiming for; birds that grew long tails with more sophisticated musculature and nervous control along with something extraordinary about the head. The cell signal for embryonic tooth formation needed to be produced in excess in the second week of incubation. What we weren't expecting is that normal sized theropod teeth, relative to the scale of specimens, automatically resulted in a more dinosaur maxilla and mandible. A keratin covering still grew over the mouth, but it didn't create a beak.</p><p>This also affected F5's behavior. Roosters are notoriously violent in contesting for mating rights, however, the F5 threat displays were far removed from your classic domesticate or wild male fowl. The vestigial traces of spurs were gone by the F3 generation. The roosters didn't quite know how to read another male's posturing, and without spurs their confrontations became bloody affairs. We had to act quickly to avoid losing our strain-- and funding.</p><p>Disaster struck our F6 generation, when hen aggression manifested against their own chicks. Twenty-six chicks were saved, but we had to euthanize all but four of the F5 adults. The differences in these generations was so extreme, that I concluded in my Stage Two abstract that a line between major taxa had been crossed.</p><p>When the F6 specimens reached adulthood, I knew that we now had real theropods roughly equal to those of the late Cretaceous that were most related to birds, but evolutionary dead ends. Most of their feathers were closer to down and lacked barbules to keep the rachis hooked together. Only on the arms did formally designated flight feathers bare any resemblance to modern birds. Nothing unexpected, really.</p><p>F8 was when we hit pay dirt. Ensuring to limit size for the bulk of Stage Three, we nonetheless brought average weight up to eleven kilograms. No longer were we keeping specimens indoors, and instead maintained an enclosure akin to biodomes used in prelude to the first lunar colony. We also stopped letting lose prey for our animals to eat, and maintained a sustainable breeding population of multiple species, enough to get four tiers of consumers with our species as top predator.</p><p>This was also the generation that no longer produced keratin over their mouths. Their plumage also started to reduce both in density and sophistication. We simulated a taxon akin to the dawn of Theropoda, and it was time to run the evolutionary clock forward again.</p><p>Stage Four of the project only needed three generations, and so we kept numbers low for ease of management. F9 grew to the size of German Shepherds, and there were early signs that the third digit of the hand was diminishing. The jaw and snout looked something like Eotyrannus, the great granddaddy of tyrannosaurs. What surprised me was the extra fluffy growth of down around the neck, liken to a mane, albeit not quite that of a lion. However, the coloration matched that of preserved Eotyrannus pigments found with a fossil some thirty years ago, so we knew we were on course.</p><p>By F10, all that was needed was to scale F9's offspring upward. This required doubling the number of wildlife handlers on-hand at all times, and a second chat with the review board regarding safety. However, the behavior of proto-tyrannosaurs drew the attention of pretty much every paleontologist on the planet.</p><p>It was expected that tyrannosaurs would rear, defend, and provide rudimentary training of their young. However, the family dynamic was entirely unanticipated. Female theropods were larger than their male counterparts, as with today's birds of prey. However, the difference and resulting body proportions borne of gender dimorphism required that males stick around to help raise young.</p><p>Unsure what ratio was needed for a goodly amount of sexual selection for mates was needed, I made a reasonably educated guess that five females and eight males should be the bare minimum. One of our top females immediately took in three of the best males, with the next two highest socially ranked females mated with a pair of males each, with the fourth female accepting the eighth male, and the fifth female being shut out entirely.</p><p>Our monogamous pair didn't stay together for long, and only one of their chicks made it past two years, having barely reached a fifth of F10's adult weight and not even a tenth of what we genetically programmed to be fully adult. However, the top three families engaged in a hunting pattern requiring divisions of labor not thought possible with theropods, even Deinonychus, now identified as the most complex pack hunter of the Cretaceous.</p><p>Yearlings were the scouts, because they were small enough not to draw fear from the cattle they surveilled. Juveniles became the marathon runners of the pride, as they were lighter in build and agile enough to coral herds the way modern sheepdogs or wolves might. Then, one or more of the males would take first bite in order to hold and weigh down the prey animal. It took the female to deliver the killing bite and, as expected, the comically undersized two-finger arms were instrumental in restraining the steer along with one of the rear legs.</p><p>From this, we concluded that extinct tyrannosaurs also practiced group hunting with division of labor specialties, partly dependent on gerontological morphology over the life of the animals. It was time to allow our evolutionary clock to strict twelve.</p><p>The breeding of Generations F10 and their very similar F11 were hard to constrain, but we did manage to prevent viable embryos beyond the one we were contractually permitted. Raised by the primary F11 proto-tyrannus family, our final specimen proved the most startling revelation as it grew. Keenly aware of factual, as well as fictional risks, we selected a male out of the viable embryos. It wasn't just for size considerations, but that the F12 offspring would've made its one and only possible gender switch from female to male, which all vertebrate males undergo before they're hatched or born.</p><p>His downy coat grew even darker in color, more so on the dorsal side, with latter bands of arcing coloration. The mane was the darkest, but the sheer thickness and length which the down grew surpassed even the most generous assessments of extinct tyrannosaurs. It led to the moniker for which the synthetic species is identified, Tyrannosaurus arctorribilis rex or Grizzly Rex.</p><p>His plumage and behavior answered questions dating back to the first tyrannosaur fossil find. The clash of whether tyrannosaurs were predators or scavengers finally settled on a niche comparable to that occupied by bears, but for the pack hunting. What's more, despite all the horror and sci-fi films spanning almost two centuries, we found Grizz's demeanor fairly tame and even-tempered. No doubt, due to being well-fed and kept away from our prior generations of reborn theropods.</p><p>Grizzly Rex did require the largest range, however, and a fenced off federal preserve was set aside for him, since the natural ecology was already devastated by mining, and only restructured in the 2050's. We tagged, chipped, and neutered Grizzly Rex before releasing him into his home turf. Thereafter, daily flights by drone or manned helicopter kept tabs on him, and we approved grants for other scientists to study Grizzly Rex in the relative wild.</p><p>I don't get out to see him as much as I used to, now that I'm retired, but I often think of Grizzly Rex and the two decades long project that made his remarkable life possible. He doesn't know it, but his survival is a torch of hope for people and countries across the world. Because of him others programs initiated to raise from the dead species our shortsightedness pushed into the grave. A grave that started to open wide enough to accept the last Homo sapiens.</p>
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